A conventional electric power steering control apparatus includes a motor having a plurality of sets of multiphase windings, and a plurality of inverter circuits for driving the respective multiphase windings of the motor independently. In a two-winding, three-phase motor (a single motor having two three-phase windings), for example, the respective three-phase windings are independent of each other, and the two independent inverter circuits likewise exist independently. Hence, the two three-phase windings do not necessarily have to be driven simultaneously, and instead, the two three-phase windings may be activated independently.
Further, when power is introduced into the conventional electric power steering control apparatus, a so-called initial check is executed to determine whether or not a fault has occurred in a motor driving unit including the plurality of multiphase windings of the motor and the plurality of inverter circuits. When a fault is not detected, electric power steering is started for the first time via the motor driving unit.
When a fault is detected, however, either the location of the fault in the motor driving unit is not used or the power supply is interrupted, depending on the content of the fault. Further, in a two-winding, three-phase motor such as that described above, a current may be supplied to the two windings simultaneously irrespective of whether or not a fault has been detected in consideration of a difference between respective drive start timings of the three-phase windings, which is due to a phase deviation between the three-phase windings in terms of respective electric angles thereof (see PTL 1, for example).